This application is based on and claims priority to Japanese Patent Application No. 2001-373759, filed Dec. 7, 2001, the entire contents of which are hereby expressly incorporated by reference.
1. Field of the Invention
The present invention is directed to a lubricant reservoir. More specifically, the present invention relates to an improved breather arrangement for a lubricant reservoir.
2. Description of Related Art
Personal watercraft have become very popular in recent years. This type of watercraft is quite sporting in nature and carries one or more riders. A relatively small hull of the personal watercraft defines a rider""s area above an engine compartment. An internal combustion engine powers a jet propulsion unit which propels the watercraft. The engine lies within the engine compartment in front of a tunnel formed on an underside of the hull. The jet propulsion unit, which includes an impeller, is placed within the tunnel. The impeller has an impeller shaft driven by the engine. The impeller shaft usually extends between the engine and the jet propulsion device through a bulkhead of the hull tunnel.
Four-stroke engines include lubrication systems arranged to supply lubrication oil to various portions of their engines, such as the crankshaft chamber and camshaft chamber. Desirably, a volume of lubrication oil is provided within a reservoir to be available for supply to the engine. The lubrication oil is permitted to cool upon being returned to the reservoir before again being supplied to the engine. As the oil pools in the reservoir, blow by gasses and air that have been entrained in the oil, aspirate out of the oil and collect in the reservoir. Vapor conduits can connect the lubricant reservoir with an induction system of the engine so as to draw out and dispose of the air and/or blow-by gasses.
One aspect of the present invention includes the realization that vapor recovery arrangements in the lubricant reservoirs of some watercraft can ingest liquid oil during normal operation. For example, with reference to FIGS. 1 and 2, the lubricant reservoir and vapor recovery arrangement 10 of a personal watercraft (not shown) is illustrated therein. The reservoir assembly and vapor recovery arrangement 10 include a lubricant tank 12 which includes a reservoir portion 14 and the vapor separator portion 16.
The reservoir portion 14 includes an inlet 18 which receives liquid lubricant L from a pump (not shown). The reservoir portion 14 also includes an outlet 20 which guides lubricant L from the reservoir portion 14 to another pump (not shown).
The vapor separator portion 16 includes a baffle 22 mounted below an upper wall of the reservoir 12. A breather chamber 24 is defined between the baffle 22 on the upper walls of the reservoir 12. The baffle 22 includes a plurality of breather apertures 26.
A conduit 27 extends from a side of the reservoir to the head of the associated engine. The conduit 27 thus allows oil overflowing within the reservoir 12 to be returned to the engine body. Additionally, blow-by gases contained within the engine body can flow into the reservoir 12. A vapor recovery conduit 28 extends from an upper wall of the reservoir 12 to a second breather chamber 29. The second breather chamber 29 defines a labyrinth path therein. The outlet of the second breather chamber 29 is connected to the induction system (not shown) of the watercraft.
In normal operation, the level of liquid lubricant L within the reservoir 12 means substantially level, as shown on FIG. 1. As the engine (not shown) of the watercraft operates, liquid lubricant L travels up the inlet portion 18 and fills the reservoir portion 14. Because the liquid lubricant L becomes entrained with air and/or blow-by gases as it moves through the engine, the air and/or blow-by gases along with some oil vapor V aspirate out of the liquid lubricant L. The vapors V travel through the apertures 26 into the breather chamber 24. From the breather chamber 24, the vapors travel through the vapor conduit 28 through the second breather chamber 29. As the vapor V travels through the labyrinth path defined within the second breather chamber 29, additional liquids, such as liquid lubricant L, precipitates out of the vapor V. The second breather chamber 29 includes a drain which allows the liquid lubricant L to return to the crankcase of the engine. The vapors that travel through the second breather chamber 29 return to the induction system of the engine for combustion within the engine.
When the watercraft is operated at elevated speed, and in particular at planing speeds, the watercraft continually jumps out of the water to varying degrees. Additionally, personal watercraft are often turned sharply during operation. It has been found that jumping and turning movements of such a watercraft tend to cause the liquid lubricant L, within the reservoir 14 to travel upwardly along the sides of the reservoir 14 toward the apertures 26. As such, an excessive amount of liquid lubricant L, which can be in the form of large droplets, enters the first breather chamber 24, and thus can enter the vapor recovery line 28. Further, it has been found that enough liquid lubricant L can travel into the first breather chamber 24 so as to hinder the performance of vapor recovery and/or be drawn into the vapor recovery line 28.
According to another aspect of the present invention, a watercraft includes a hull into an engine disposed within the hull. The engine includes a lubrication and vapor recovery arrangement including a lubricant reservoir in the breather assembly within the reservoir. The breather assembly includes at least one baffle defining a breather chamber within a lubricant reservoir. The baffle includes at least one aperture allowing vapor from the lubricant reservoir to flow into the breather chamber. Additionally, a wall extends downwardly from a lower surface of the breather assembly, around the periphery of the at least one aperture.
By providing the wall disposed around the periphery of the aperture in the baffle, less oil can enter the breather chamber. For example, when the watercraft is operated at a planing speed which it jumps out of the water and/or operated through highspeed turns, lubricant is urged upwardly along the sides of the lubricant reservoir towards the apertures. As the lubricant travels up the sides of the walls and hits the baffle, the lubricant is turned inwardly towards the apertures. The wall disposed around the periphery of the aperture helps divert the liquid lubricant away from the apertures. Thus, the baffle arrangement according to the present invention helps prevent oil from entering the breather chamber and thus impeding the operation of the breather assembly.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow.